The present invention relates to a foam pump assembly usable to make foam for use as personal care and/or hygiene products such as hand soap, moisturizers, sanitizers, shampoo, shower gels, and shaving cream, for example.
There are a number of commercial foam pumps and pump engines on the market today available from companies such as Arminak and Associates, Airspray, K&K, and others. Some patents relating to such foam pumps are U.S. Pat. Nos. 5,271,530; 5,443,569; 5,445,288; 6,053,364 and 6,082,586, all of which are incorporated by reference herein. Such foam pumps typically comprise a pump engine connected to a liquid container. The overall assembly typically has an air chamber with an air inlet and air outlet, a liquid chamber with a liquid inlet and liquid outlet, a mixing chamber, an actuator for working the pump so that air from the air chamber and liquid from the liquid chamber is fed to the mixing chamber to create foam. These pumps typically have a porous member in the form of a planar mesh or screen having a large number of pores.
The porous member is typically located after the mixing chamber and is asserted to help improve the foam characteristics in some way, possibly by helping to create the foam or to homogenize the foam to provide a relatively uniform air bubble size for the foam.
However, such a porous member can become at least partly clogged when the mixture oxidizes or dries out, especially when the pump is unused for an extended period. Although the mesh pore size may be different for different applications, the pore size is typically relatively small which tends to make the porous member more susceptible to clogging. The porous member may also be difficult to fabricate and may also make the pump more costly.